drivers/platform/x86/simatic-ipc.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Siemens SIMATIC IPC platform driver
   4  *
   5  * Copyright (c) Siemens AG, 2018-2021
   6  *
   7  * Authors:
   8  *  Henning Schild <henning.schild@siemens.com>
   9  *  Jan Kiszka <jan.kiszka@siemens.com>
  10  *  Gerd Haeussler <gerd.haeussler.ext@siemens.com>
  11  */
  12
  13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  14
  15 #include <linux/dmi.h>
  16 #include <linux/kernel.h>
  17 #include <linux/module.h>
  18 #include <linux/pci.h>
  19 #include <linux/platform_data/x86/simatic-ipc.h>
  20 #include <linux/platform_device.h>
  21
  22 static struct platform_device *ipc_led_platform_device;
  23 static struct platform_device *ipc_wdt_platform_device;
  24
  25 static const struct dmi_system_id simatic_ipc_whitelist[] = {
  26         {
  27                 .matches = {
  28                         DMI_MATCH(DMI_SYS_VENDOR, "SIEMENS AG"),
  29                 },
  30         },
  31         {}
  32 };
  33
  34 static struct simatic_ipc_platform platform_data;
  35
  36 static struct {
  37         u32 station_id;
  38         u8 led_mode;
  39         u8 wdt_mode;
  40 } device_modes[] = {
  41         {SIMATIC_IPC_IPC127E, SIMATIC_IPC_DEVICE_127E, SIMATIC_IPC_DEVICE_NONE},
  42         {SIMATIC_IPC_IPC227D, SIMATIC_IPC_DEVICE_227D, SIMATIC_IPC_DEVICE_NONE},
  43         {SIMATIC_IPC_IPC227E, SIMATIC_IPC_DEVICE_427E, SIMATIC_IPC_DEVICE_227E},
  44         {SIMATIC_IPC_IPC277E, SIMATIC_IPC_DEVICE_NONE, SIMATIC_IPC_DEVICE_227E},
  45         {SIMATIC_IPC_IPC427D, SIMATIC_IPC_DEVICE_427E, SIMATIC_IPC_DEVICE_NONE},
  46         {SIMATIC_IPC_IPC427E, SIMATIC_IPC_DEVICE_427E, SIMATIC_IPC_DEVICE_427E},
  47         {SIMATIC_IPC_IPC477E, SIMATIC_IPC_DEVICE_NONE, SIMATIC_IPC_DEVICE_427E},
  48 };
  49
  50 static int register_platform_devices(u32 station_id)
  51 {
  52         u8 ledmode = SIMATIC_IPC_DEVICE_NONE;
  53         u8 wdtmode = SIMATIC_IPC_DEVICE_NONE;
  54         int i;
  55
  56         platform_data.devmode = SIMATIC_IPC_DEVICE_NONE;
  57
  58         for (i = 0; i < ARRAY_SIZE(device_modes); i++) {
  59                 if (device_modes[i].station_id == station_id) {
  60                         ledmode = device_modes[i].led_mode;
  61                         wdtmode = device_modes[i].wdt_mode;
  62                         break;
  63                 }
  64         }
  65
  66         if (ledmode != SIMATIC_IPC_DEVICE_NONE) {
  67                 platform_data.devmode = ledmode;
  68                 ipc_led_platform_device =
  69                         platform_device_register_data(NULL,
  70                                 KBUILD_MODNAME "_leds", PLATFORM_DEVID_NONE,
  71                                 &platform_data,
  72                                 sizeof(struct simatic_ipc_platform));
  73                 if (IS_ERR(ipc_led_platform_device))
  74                         return PTR_ERR(ipc_led_platform_device);
  75
  76                 pr_debug("device=%s created\n",
  77                          ipc_led_platform_device->name);
  78         }
  79
  80         if (wdtmode != SIMATIC_IPC_DEVICE_NONE) {
  81                 platform_data.devmode = wdtmode;
  82                 ipc_wdt_platform_device =
  83                         platform_device_register_data(NULL,
  84                                 KBUILD_MODNAME "_wdt", PLATFORM_DEVID_NONE,
  85                                 &platform_data,
  86                                 sizeof(struct simatic_ipc_platform));
  87                 if (IS_ERR(ipc_wdt_platform_device))
  88                         return PTR_ERR(ipc_wdt_platform_device);
  89
  90                 pr_debug("device=%s created\n",
  91                          ipc_wdt_platform_device->name);
  92         }
  93
  94         if (ledmode == SIMATIC_IPC_DEVICE_NONE &&
  95             wdtmode == SIMATIC_IPC_DEVICE_NONE) {
  96                 pr_warn("unsupported IPC detected, station id=%08x\n",
  97                         station_id);
  98                 return -EINVAL;
  99         }
 100
 101         return 0;
 102 }
 103
 104 /* FIXME: this should eventually be done with generic P2SB discovery code
 105  * the individual drivers for watchdogs and LEDs access memory that implements
 106  * GPIO, but pinctrl will not come up because of missing ACPI entries
 107  *
 108  * While there is no conflict a cleaner solution would be to somehow bring up
 109  * pinctrl even with these ACPI entries missing, and base the drivers on pinctrl.
 110  * After which the following function could be dropped, together with the code
 111  * poking the memory.
 112  */
 113 /*
 114  * Get membase address from PCI, used in leds and wdt module. Here we read
 115  * the bar0. The final address calculation is done in the appropriate modules
 116  */
 117 u32 simatic_ipc_get_membase0(unsigned int p2sb)
 118 {
 119         struct pci_bus *bus;
 120         u32 bar0 = 0;
 121         /*
 122          * The GPIO memory is in bar0 of the hidden P2SB device.
 123          * Unhide the device to have a quick look at it, before we hide it
 124          * again.
 125          * Also grab the pci rescan lock so that device does not get discovered
 126          * and remapped while it is visible.
 127          * This code is inspired by drivers/mfd/lpc_ich.c
 128          */
 129         bus = pci_find_bus(0, 0);
 130         pci_lock_rescan_remove();
 131         pci_bus_write_config_byte(bus, p2sb, 0xE1, 0x0);
 132         pci_bus_read_config_dword(bus, p2sb, PCI_BASE_ADDRESS_0, &bar0);
 133
 134         bar0 &= ~0xf;
 135         pci_bus_write_config_byte(bus, p2sb, 0xE1, 0x1);
 136         pci_unlock_rescan_remove();
 137
 138         return bar0;
 139 }
 140 EXPORT_SYMBOL(simatic_ipc_get_membase0);
 141
 142 static int __init simatic_ipc_init_module(void)
 143 {
 144         const struct dmi_system_id *match;
 145         u32 station_id;
 146         int err;
 147
 148         match = dmi_first_match(simatic_ipc_whitelist);
 149         if (!match)
 150                 return 0;
 151
 152         err = dmi_walk(simatic_ipc_find_dmi_entry_helper, &station_id);
 153
 154         if (err || station_id == SIMATIC_IPC_INVALID_STATION_ID) {
 155                 pr_warn("DMI entry %d not found\n", SIMATIC_IPC_DMI_ENTRY_OEM);
 156                 return 0;
 157         }
 158
 159         return register_platform_devices(station_id);
 160 }
 161
 162 static void __exit simatic_ipc_exit_module(void)
 163 {
 164         platform_device_unregister(ipc_led_platform_device);
 165         ipc_led_platform_device = NULL;
 166
 167         platform_device_unregister(ipc_wdt_platform_device);
 168         ipc_wdt_platform_device = NULL;
 169 }
 170
 171 module_init(simatic_ipc_init_module);
 172 module_exit(simatic_ipc_exit_module);
 173
 174 MODULE_LICENSE("GPL v2");
 175 MODULE_AUTHOR("Gerd Haeussler <gerd.haeussler.ext@siemens.com>");
 176 MODULE_ALIAS("dmi:*:svnSIEMENSAG:*");